Dental implants corrosion

Cobalt—Chromium Alloys. Co—Cr and Ni—Cr alloys are used predominately for the casting of removable partial dentures fixed partial dentures (bridges), crowns, and inlays are also cast. Because of high hardness, corrosion resistance, and wear resistance cobalt-chromium alloys are used for bite adjustments and as serrated inserts in plastic teeth used in fliU dentures. These alloys are well tolerated by the body and also are used for dental implants and orthopedic implant alloys. 

Surface preparation of the dental implant prior to implantation wiH have an effect on corrosion behavior, initial metal ion release, and interface tissue response (316). The titanium and titanium aHoy dental implants in present use have many forms to assist bone ingrowth attachment including cylinders with holes, screw threaded surfaces, porous surfaces, and other types of roughened surfaces. Methods used to produce porous surfaces iaclude arc plasma... 

Various materials are used in dental prosthetic practice for the preparation of dental implants, crowns, and bridges. Some of these materials contain copper, which is added in order to improve mechanical or/and chemical properties, but some of them may contain the copper as an impurity. Considering the fact that dental implants remain in the oral cavity for a long time, and that they are exposed to the corrosive action of oral fluids and various kinds of food and beverages, it is necessary to check their possible harmful effects upon the human health. 

Although titanium has a large positive E° for oxidation, and T dust will burn in air, the bulk metal is remarkably immune to corrosion because its surface becomes coated with a thin, protective oxide film. Titanium objects are inert to seawater, nitric acid, hot aqueous NaOH, and even to aqueous chlorine gas. Titanium is therefore used in chemical plants, in desalination equipment, and in numerous other industrial processes that demand inert, noncorrosive materials. Because it is nontoxic and inert to body fluids, titanium is even used for manufacturing artificial joints and dental implants. 

Titaiuum is a silvery ductile metal with important industrial uses because it is less dense than iron, much stronger than aluminum, and almost as corrosion resistant as platinum. This rare combination of properties makes it ideal for a variety of uses, particularly in engines, aircraft frames, marine equipment, and industrial plants. Titanium metal and alloys also replace bone and serve in dental implants. At normal... 

Alumina is a well-known bioinert ceramic material which can be used in total hip prosthesis and dental implants since it exhibits good biocompatibility, strength, and excellent corrosion resistance.70,71 The application of alumina has some limitations due to poor fracture toughness. The incorporation of ductile phase may lead to the... 

Van Orden, A. 1985. Corrosive response of the interface tissue to 316L stainless steel, Ti-based alloy and cobalt-based alloys. In The Dental Implant, R. McKinney and J.E. Lemons (Eds.), pp. 1-25, Littleton, PSG. 

H. Arslan, H. CeHkkan, N. Omek, O. Ozan, M.L. Aksu, A.E. Ersoy, Galvanic corrosion of titanium-based dental implant materials, J. Appl. Electrochem. 38 (2008) 853—859. 

Anodized films are most often applied to protect aluminum alloys. However there are processes for other metals such as titanium, zinc, and magnesium. Anodized titanium is used in dental implants and sometimes in art and costume jewelry because it generates various colors without dyes. Each color depends on a specific thickness of the oxide [9]. To ensure the preparation of a consistent oxide layer, one must control conditions such as electrolytic concentrations, acidity, and current. Also a sealing process is often needed to achieve corrosion resistance because thick coatings (oxide layers) are generally porous. 

Fathi MH, Salehi M, Saatchi A, Mortazavi V, Moosavi SB (2003) In vitro corrosion behavior of bioceramic, metallic, and bioceramic-metallic coated stainless steel dental implants. Dent Mater 19(3) 188-198... 

Titanium is a successful biocompatible material that is extensively used today for manufacturing bone-anchoring systems, such as dental implants or hip-joint fixation and replacement, as well as for pacemakers, heart valves, and ear-drum drainage tubes. It has advantageous bulk and surface properties in particular, a low modulus of elasticity, a high strength-to-weight ratio, excellent resistance to corrosion, and an inert, biocompatible surface oxide film. The surface chemistry and structure are prime... 

Bidez, M. W., Lemons, J. E., and Isenberg, B. P., A Corrosion Study of Gold and Nickel-Based Dental Systems Using Distal Abutment Dental Implants, World Congress in Biomaterials, Paper 60, Society for Biomaterials, Washington, DC, 1984. 

Temperature is an important factor influencing in vivo electrochemical behavior. Internal body temperature is homeo-statically regulated at 37 C, so it is important to test at this value in the laboratory. For dental materials exposed to the oral cavity, the temperature fluctuates due to food cind drink intake and can range from about 0-70°C. Dissolved salts, particularly chlorides, are probably the most influential components for implant corrosion in vivo [2], although by no means the only ones. The internal body electrolyte has the equivalent of 0.9 % NaCl in solution. 

In dentistry, the presence of amalgams and various alloys in the mouth poses potential corrosion problems if an electrical cormection occur-s. Growing numbers of dental implants increase the possibility for corrosion in the mouth, and consideration should be given to suprastructure metals that are irsed with implants. 

Fraker, A. C., Van Orden, A. C., Sung, P., and Hahn, H., Corrosive Response of the Interface Tissue to Dental Implants, Implant Prosthodontics Surgical and Prosthetic Techniques for Dental Implants, M. J. Fagan, Jr. et al., Eds., Yearbook Medical Publishers, Littleton, MA, 1991, pp. 293-304. 

Some metals are used as passive substitutes for hard tissue replacement such as total hip and knee joints, for fracture healing aids as bone plates and screws, spinal fixation devices, and dental implants because of their excellent mechanical properties and corrosion resistance. Some metallic alloys are used for more active roles in devices such as vascular stents, catheter guide wires, orthodontic archwires, and cochlea implants. 

Metallic corrosion, in dental implants, 45-32 Metallic implants corrosion, 38-13-38-18... 

This chapter presents the current trends in this area with emphasis on load-bearing orthopaedic and dental implants. A detailed account on the general and the localized corrosion of conventional metalhc implants is provided. Novel fabrication strategies of nanostructured hydroxyapatite-based coatings and their roles as barrier coatings are presented. Impacts of nanoscale surface modifications on the corrosion resistance of permanent implants and novel bioresorbable implants based on magnesium alloys are highhghted. 

General and localized corrosion in orthopaedics and dental implants... 

There are no comprehensive standards or literature available on the corrosion behaviour of such nanostmctured implants. Figure 15.4 schematically represents a few likely outcomes. The following sections discuss the effeets of these modifications on the corrosion resistance of orthopaedic and dental implants More specifically, Section 15.4 discusses the effect of nanoscale surface modifications on the corrosion behaviour of titanium based alloys. Section 15.5 discusses nanoceramic coatings with emphasis on HA coatings. Current approaches in making nanostmctured coatings and nanocomposites for Mg based resorbable implants are presented in Section 15.6. 

Kumar, S. and Sankara Narayanan, T. S. N. (2008), Corrosion behaviour ofTi-15Mo alloy for dental implant applications . Journal of Dentistry, 36,500-7. 

M. Sharma, A. V. Ramesh Kumar, N. Singh, N. Adya, and B. Saluja, Electrochemical corrosion behavior of dental/implant alloys in artificial saliva, Journal of Materials Engineering and Performance, vol. 17, no. 5, pp. 695-701, 2008. 

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